Physiological monitoring devices having sensing elements decoupled from body motion

ABSTRACT

A monitoring device includes a sensor band configured to be secured around an appendage of a subject, a sensing element secured to the sensor band, a second band configured to be secured to the appendage of the subject in adjacent, spaced-apart relationship with the sensor band, and at least one member connecting the sensor band and the second band. The sensor band has a first mass and the sensing element has a second mass that is less than the first mass. The sensing element is movably secured to the sensor band via a biasing element, and the biasing element is configured to urge the sensing element into contact with a portion of the appendage. The biasing element o decouples motion of the sensor band from the sensing element, and the at least one member decouples motion between the sensor band and the second band.

RELATED APPLICATION

This application is a continuation application of pending U.S. patentapplication Ser. No. 14/761,462, filed Jul. 16, 2015, which is a 35U.S.C. § 371 national stage application of PCT Application No.PCT/US2014/012909, filed on Jan. 24, 2014, which claims the benefit ofand priority to U.S. Provisional Patent Application No. 61/757,504 filedJan. 28, 2013, the disclosures of which are incorporated herein byreference as if set forth in their entireties. The above-referenced PCTInternational Application was published in the English language asInternational Publication No. WO 2014/116924 on Jul. 31, 2014.

FIELD OF THE INVENTION

The present invention relates generally to monitoring devices and, moreparticularly, to monitoring devices for measuring physiologicalinformation.

BACKGROUND OF THE INVENTION

Photoplethysmography (PPG) is based upon shining light into the humanbody and measuring how the scattered light intensity changes with eachpulse of blood flow. The scattered light intensity will change in timewith respect to changes in blood flow or blood opacity associated withheart beats, breaths, blood oxygen level (SpO₂), and the like. Such asensing methodology may require the magnitude of light energy reachingthe volume of flesh being interrogated to be steady and consistent sothat small changes in the quantity of scattered photons can beattributed to varying blood flow. If the incidental and scattered photoncount magnitude changes due to light coupling variation between thesource or detector and the skin surface, then the signal of interest canbe difficult to ascertain due to large photon count variability causedby loss or variation of optical coupling. Changes in the surface area(and volume) of skin being impacted with photons, or varying skinsurface curvature reflecting significant portions of the photons mayalso significantly impact optical coupling efficiency. Physicalactivity, such a walking, cycling, running, etc., may cause motionartifacts in the optical scatter signal from the body, and time-varyingchanges in photon intensity due to motion artifacts may swamp-outtime-varying changes in photon intensity due to blood flow changes. Eachof these changes in optical coupling can affect the photonicinterrogation count by a large percent of the total photon count anddiminish the quality of the signal of interest; with lower probabilityof obtaining accurate values of desired data.

An earphone is a good choice for incorporation of a photoplethysmographdevice because it is a form factor that individuals are familiar with,it is a device that is commonly worn for long periods of time, and itfrequently is used during exercise which is a time when individuals maybenefit most from having accurate heart rate data (or otherphysiological data). Unfortunately, incorporation of aphotoplethysmograph device into an earphone poses several challenges.For example, earphones may be uncomfortable to wear for long periods oftime, particularly if they deform the ear surface. Moreover, human earanatomy may vary significantly from person to person, so finding anearbud form that will fit comfortably in many ears may pose significantchallenges. In addition, earbuds made for vigorous physical activitytypically incorporate an elastomeric surface and/or elastomeric featuresto function as springs that dampen earbud acceleration within the ear.Although, these features may facilitate retention of an earbud within anear during high acceleration and impact modalities, they do notadequately address optical skin coupling requirements needed to achievequality photoplethysmography.

Conventional photoplethysmography devices, as illustrated for example inFIGS. 1A-1C, typically suffer from reduced skin coupling as a result ofsubject motion. For example, most conventional photoplethysmographydevices use a spring to clip the sensor onto either an earlobe (FIG. 1A)or a fingertip (FIG. 1B). Unfortunately, these conventional devices tendto have a large mass and may not maintain consistent skin contact whensubjected to large accelerations, such as when a subject is exercising.

A conventional earbud device that performs photoplethysmography in theear is the MX-D100 player from Perception Digital of Wanchai, Hong Kong(www.perceptiondigital.com). This earbud device, illustrated in FIG. 1Cand indicated as 10, incorporates a spring 12 to improve PPG signalquality. However, the spring 12 forcibly presses the entire earbud 10within the ear E of a subject to minimize motion of the entire earbud10. There are several drawbacks to the device 10 of FIG. 1C. Forexample, the source/sensor module is coupled to the entire earbud massand, as such, may experience larger translation distances resulting ingreater signal variability when the ear undergoes accelerations. Inaddition, because the earbud 10 is held in place with one primary springforce direction, significant discomfort can be experienced by the enduser. Moreover, the earbud motion is only constrained in one directiondue to the single spring force direction.

SUMMARY

It should be appreciated that this Summary is provided to introduce aselection of concepts in a simplified form, the concepts being furtherdescribed below in the Detailed Description. This Summary is notintended to identify key features or essential features of thisdisclosure, nor is it intended to limit the scope of the invention.

Some embodiments of the present invention put a module containing one ormore energy emitters and energy detectors on a biasing element, such asan elastomeric arm that decouples earbud vibration from sensorvibration. Moreover, the biasing element urges the sensor module intointimate contact with the skin surface.

According to some embodiments of the present invention, a monitoringdevice includes a biasing element having opposite first and second endportions, and a sensing element attached to the biasing element secondend portion. The monitoring device is configured to be attached to anear of a subject such that the biasing element first end portion engagesthe ear at a first location and such that the sensing element is urgedby the biasing member into contact with the ear at a second location.The sensing element includes at least one energy emitter configured todirect energy at a target region of the ear and at least one detectorconfigured to detect an energy response signal from the target region ora region adjacent the target region. For example, the at least oneenergy emitter is configured to direct electromagnetic radiation,mechanical energy, acoustical energy, electrical energy, and/or thermalenergy at the target region, and the at least one detector is configuredto detect electromagnetic radiation, mechanical energy, acousticalenergy, electrical energy, and/or thermal energy. In some embodiments,the at least one energy emitter comprises at least one optical emitterand the at least one detector comprises at least one optical detector.

In some embodiments of the present invention, the sensing elementincludes a surface having at least one window through which energypasses from the at least one energy emitter, and through which energy iscollected by the at least one detector. The at least one window mayinclude at least one opening. Moreover, the surface may be shaped toconform to a shape of a portion of the ear of a subject.

In some embodiments of the present invention, the sensing element mayinclude a signal processor configured to receive and process signalsproduced by the at least one detector.

In some embodiments of the present invention, the biasing element mayinclude a motion sensor that is configured to detect motion of thebiasing element and/or sensing element. The motion sensor may be, forexample, an inertial sensor, a piezoelectric sensor, an optical sensor,etc. In some embodiments, the motion sensor may be aphotoplethysmography (PPG) sensor used for measuring blood flow.

According to other embodiments of the present invention, a monitoringdevice includes a biasing element having opposite first and second endportions, an earbud attached to the biasing element first end portion,and a sensing element attached to the biasing element second endportion. The earbud has a first mass, and the sensing element has asecond mass that is less than the first mass. The biasing element isconfigured to urge the sensing element into contact with a portion ofthe ear when the earbud is inserted into the ear. In addition, thebiasing element decouples motion of the earbud from the sensing element.

The sensing element includes at least one energy emitter configured todirect energy at a target region of the ear and at least one detectorconfigured to detect an energy response signal from the target regionand/or a region adjacent the target region. For example, the at leastone energy emitter is configured to direct electromagnetic radiation,mechanical energy, acoustical energy, electrical energy, and/or thermalenergy at the target region, and the at least one detector is configuredto detect electromagnetic radiation, mechanical energy, acousticalenergy, electrical energy, and/or thermal energy. In some embodiments,the at least one energy emitter comprises at least one optical emitterand the at least one detector comprises at least one optical detector.

In some embodiments, the earbud includes an optical emitter. A lightguide having a distal end terminates adjacent a window in a surface ofthe sensing element. The light guide is in optical communication withthe optical emitter and is configured to deliver light from the opticalemitter into an ear region of the subject via the light guide distalend. In some embodiments, the light guide extends from the opticalemitter to the sensing element at least partially through the biasingelement.

In some embodiments, the earbud includes an optical detector. A lightguide having a distal end terminates adjacent a window in a surface ofthe sensing element. The light guide is in optical communication withthe optical detector and is configured to collect light from an earregion of the subject via the light guide distal end and delivercollected light to the optical detector. In some embodiments, the lightguide extends from the optical detector to the sensing element at leastpartially through the biasing element.

In some embodiments of the present invention, the sensing elementincludes a surface having at least one window through which energypasses from the at least one energy emitter, and through which energy iscollected by the at least one detector. The at least one window mayinclude at least one opening. In addition, the surface may be shaped toconform to a shape of a portion of the ear of a subject.

In some embodiments of the present invention, the sensing element mayinclude a signal processor configured to receive and process signalsproduced by the at least one detector.

In some embodiments of the present invention, the biasing element mayinclude a motion sensor that is configured to detect motion of thebiasing element and/or sensing element. The motion sensor may be, forexample, an inertial sensor, a piezoelectric sensor, etc.

In some embodiments of the present invention, a speaker is disposedwithin the earbud, and the earbud includes at least one aperture throughwhich sound from the speaker can pass.

According to other embodiments of the present invention, a monitoringdevice includes a housing configured to be attached to an ear of asubject and a sensing element movably secured to the housing via abiasing element. The housing has a first mass, and the sensing elementhas a second mass that is less than the first mass. In some embodiments,the first mass is at least 1.25 times greater than the second mass. Thebiasing element is configured to urge the sensing element into contactwith a portion of the ear, and decouples motion of the housing from thesensing element.

The sensing element includes at least one energy emitter configured todirect energy at a target region of the ear and at least one detectorconfigured to detect an energy response signal from the target region ora region adjacent the target region. For example, the at least oneenergy emitter is configured to direct electromagnetic radiation,mechanical energy, acoustical energy, electrical energy, and/or thermalenergy at the target region, and the at least one detector is configuredto detect electromagnetic radiation, mechanical energy, acousticalenergy, electrical energy, and/or thermal energy. In some embodiments,the at least one energy emitter comprises at least one optical emitterand the at least one detector comprises at least one optical detector.

In some embodiments, the biasing element includes a motion sensorconfigured to detect motion of the biasing element and/or sensingelement.

In some embodiments, the biasing element comprises a flexible memberthat at least partially surrounds the sensing element. The flexiblemember comprises a compressible, resilient material, such as gel. Insome embodiments, the monitoring device includes a speaker within thehousing. A sound port is formed through the flexible member and housingso as to be in acoustical communication with the speaker.

Earbud monitoring devices, according to embodiments of the presentinvention, are advantageous over conventional monitoring devices forseveral reasons. One is comfort of fit. An earbud monitoring deviceaccording to embodiments of the present invention is comfortable and mayprovide more accurate biometrics than conventional earbuds. Moreover, bydesigning the sensor element as a separate body from the earbud, theearbud can be tailored for comfort. Another advantage is that byproviding supplemental spring action on the sensor module an additionallevel of sensor to skin intimacy may be achieved. By decoupling thesensor module and earbud, less spring force (pressure) is needed tomaintain sensor contact with the ear, thus resulting in greater comfort.A device where the sensor can stay in contact with the interrogationarea of interest, even under extreme accelerations, may be able tocontinuously report data and offer the end-user a higher confidencelevel in the device's accuracy.

According to other embodiments of the present invention, a monitoringdevice includes a sensor band configured to be secured around anappendage of a subject, and a sensing element movably secured to thesensor band via a biasing element. The sensor band has a first mass, andthe sensing element has a second mass that is less than the first mass.In some embodiments, the first mass is at least 1.25 times greater thanthe second mass. The biasing element is configured to urge the sensingelement into contact with a portion of the appendage, and the biasingelement decouples motion of the band from the sensing element.

The sensing element includes at least one energy emitter configured todirect energy at a target region of the body and at least one detectorconfigured to detect an energy response signal from the target region ora region adjacent the target region. For example, the at least oneenergy emitter is configured to direct electromagnetic radiation,mechanical energy, acoustical energy, electrical energy, and/or thermalenergy at the target region, and the at least one detector is configuredto detect electromagnetic radiation, mechanical energy, acousticalenergy, electrical energy, and/or thermal energy. In some embodiments,the at least one energy emitter comprises at least one optical emitterand the at least one detector comprises at least one optical detector.In some embodiments, the biasing element includes a motion sensorconfigured to detect motion of the biasing element and/or sensingelement.

In some embodiments, the monitoring device includes a second band thatis configured to be secured to the appendage of the subject in adjacent,spaced-apart relationship with the sensor band. At least one member orbridge connects the sensor band and second band together.

According to other embodiments of the present invention, a monitoringdevice includes a band that is configured to be secured around anappendage of a subject, wherein the band comprises an inner surface andan outer surface. A plurality of biasing elements extend radiallyoutward from the inner surface in circumferential spaced-apartrelationship and are configured to contact the appendage. A sensingelement is secured to the band inner surface between two of the biasingelements. In some embodiments, the sensing element extends outwardlyfrom the band inner surface such that the at least one energy emitterand at least one detector associated with the sensing element do notcontact the appendage when the band is secured around the appendage. Inother embodiments, the sensing element extends outwardly from the bandinner surface such that the at least one energy emitter and at least onedetector associated with the sensing element contact the appendage whenthe band is secured around the appendage.

The at least one energy emitter is configured to direct electromagneticradiation, mechanical energy, acoustical energy, electrical energy,and/or thermal energy at the target region, and the at least onedetector is configured to detect electromagnetic radiation, mechanicalenergy, acoustical energy, electrical energy, and/or thermal energy. Insome embodiments, the at least one energy emitter comprises at least oneoptical emitter and the at least one detector comprises at least oneoptical detector.

According to other embodiments of the present invention, a monitoringdevice includes a band that is configured to be secured around anappendage of a subject and includes an inner surface and an outersurface. An elongated biasing element having opposite ends is securedcircumferentially to the band inner surface such that the opposite endsare in adjacent, spaced-apart relationship. The biasing elementcomprises a surface that contacts the appendage when the band is securedaround the appendage. A sensing element is secured to the band innersurface between the adjacent, spaced-apart biasing element ends.

The sensing element includes at least one energy emitter configured todirect energy at a target region of the appendage and at least onedetector configured to detect an energy response signal from the targetregion or region adjacent to the target region. The at least one energyemitter is configured to direct electromagnetic radiation, mechanicalenergy, acoustical energy, electrical energy, and/or thermal energy atthe target region, and the at least one detector is configured to detectelectromagnetic radiation, mechanical energy, acoustical energy,electrical energy, and/or thermal energy. In some embodiments, the atleast one energy emitter comprises at least one optical emitter and theat least one detector comprises at least one optical detector. In someembodiments, the sensing element includes a surface having at least onewindow through which energy passes from the at least one energy emitter,and through which energy is collected by the at least one detector.

In some embodiments, the sensing element extends outwardly from the bandinner surface such that the at least one energy emitter and at least onedetector associated with the sensing element do not contact theappendage when the band is secured around the appendage. In otherembodiments, the sensing element extends outwardly from the band innersurface such that the at least one energy emitter and at least onedetector associated with the sensing element contact the appendage whenthe band is secured around the appendage.

In some embodiments, one or more portions of the biasing element surfacehave a textured configuration, such as a plurality of raised bumps. Theraised bumps may be arranged in an array and may have various shapes andsizes. In some embodiments, the plurality of raised bumps havealternating shapes.

Embodiments of the present invention utilize a sensing element as adistinct third body relative to a monitoring device and a body of asubject wearing the monitoring device. For example, if the monitoringdevice is an earbud configured to be secured within the ear of asubject, the ear of the subject is the first body, the earbud is thesecond body, and the sensing element or module is a distinct third body.As such, embodiments of the present invention provide several advantagesover conventional monitoring devices. First, the mass of the sensingelement, according to embodiments of the present invention, is reducedsince the sensing element is decoupled from the earbud body. This lowermass may see smaller displacements as a result of ear, earbud orappendage accelerations, for example, as a result of subject motion.Second, a sensing element, according to embodiments of the presentinvention, can be shaped and presented to the interrogation surface ofinterest in a form tailored for optical coupling and not restricted byconventional forms, such as conventional earbud forms.

In addition, the effect of earbud cabling pulling on an earbud andpossibly dislodging the sensor to skin contact can be minimized byhaving a biasing element, such as a spring, between the earbud and thesensor, according to embodiments of the present invention. Byincorporating a biasing element between an earbud and sensor, fit withinone or more portions of the concha of an ear can be achieved with anoptimized earbud form, while fit between the sensor and interrogationsurface can be optimized for photoplethysmography. Moreover, because anydampened system will have a lag in response to vibrational compensation,decoupling the sensor element from earbud motion allows the sensorresponse to be better tuned to managing small vibrational offsets;whereas, the earbud dampening structures are best designed to handlelarger displacements inherent from a larger, heavier mass body withmultiple ear contact points. The earbud makes larger amplitudeacceleration compensations compared to the sensor element due to itslarger mass. The secondary minor acceleration compensations of thesensor to ear surface (or appendage) movement may be significantlyreduced as well as signal variation.

It is noted that aspects of the invention described with respect to oneembodiment may be incorporated in a different embodiment although notspecifically described relative thereto. That is, all embodiments and/orfeatures of any embodiment can be combined in any way and/orcombination. Applicant reserves the right to change any originally filedclaim or file any new claim accordingly, including the right to be ableto amend any originally filed claim to depend from and/or incorporateany feature of any other claim although not originally claimed in thatmanner. These and other objects and/or aspects of the present inventionare explained in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which form a part of the specification,illustrate various embodiments of the present invention. The drawingsand description together serve to fully explain embodiments of thepresent invention.

FIG. 1A is a perspective view of a conventional photoplethysmographydevice attached to the ear of a person.

FIG. 1B is a perspective view of a conventional photoplethysmographydevice attached to a finger of a person.

FIG. 1C illustrates a conventional photoplethysmography device attachedto the ear of a person, and wherein a biasing element is utilized toretain the photoplethysmography device in the person's ear.

FIGS. 2A-2C are perspective views of a monitoring device having anearbud and a sensing element attached to the earbud via a biasingmember, according to some embodiments of the present invention, andwherein the biasing member is configured to decouple motion of theearbud from the sensing element.

FIG. 3 schematically illustrates a sensing element utilized inmonitoring devices, according to some embodiments of the presentinvention.

FIG. 4 illustrates the monitoring device of FIGS. 2A-2C secured withinthe ear of a person.

FIG. 5A is a perspective view of a monitoring device for attachment toan ear of a person, according to some embodiments of the presentinvention, and wherein a sensor module is movably secured to the housingof the monitoring device to decouple motion of the housing from thesensor module.

FIG. 5B is an exploded, perspective view of the monitoring device ofFIG. 5A.

FIG. 6 illustrates elongated light guides that may be utilized withmonitoring devices, according to some embodiments of the presentinvention, such that an optical emitter and optical detector can belocated remotely from a sensing element of a monitoring device.

FIG. 7 illustrates the monitoring device of FIGS. 2A-2C with an opticalemitter and detector located within the earbud and with elongated lightguides extending from the optical emitter and detector to the sensingelement, according to some embodiments of the present invention.

FIG. 8 illustrates a human ear with various portions thereof labeled andwith the monitoring device of FIG. 11 secured therewithin.

FIG. 9 illustrates a human ear with various portions thereof labeled andwith the monitoring device of FIG. 10 secured therewithin.

FIG. 10 is a perspective view of a monitoring device having a sensormodule configured to be attached to an ear of a person via a biasingmember, according to some embodiments of the present invention, andwherein the biasing member is configured to decouple motion of the earfrom the sensor module.

FIG. 11 is a perspective view of a monitoring device having astabilizing member configured to be inserted within an ear of a personand a sensor module attached to the stabilizing member via a biasingmember, according to some embodiments of the present invention, andwherein the biasing member is configured to decouple motion of thestabilizing member from the sensor module.

FIG. 12 illustrates a monitoring device configured to be secured to anappendage of a subject, according to some embodiments of the presentinvention.

FIG. 13 is a partial perspective view of the monitoring device of FIG.12 illustrating a sensor band and a sensing element movably secured tothe sensor band via a biasing element.

FIG. 14 illustrates a monitoring device configured to be secured to anappendage of a subject, according to some embodiments of the presentinvention.

FIG. 15 is a partial view of the monitoring device of FIG. 14illustrating a sensing element secured to the band inner surface betweentwo of the biasing elements.

FIG. 16 illustrates a monitoring device configured to be secured to anappendage of a subject, according to some embodiments of the presentinvention.

FIG. 16A is a partial view of the monitoring device of FIG. 16illustrating a sensing element secured to the band inner surface betweentwo of the biasing elements.

FIG. 17 illustrates a monitoring device configured to be secured to anappendage of a subject, according to some embodiments of the presentinvention.

FIG. 17A is a partial view of the monitoring device of FIG. 17illustrating a sensing element secured to the band inner surface.

FIG. 17B is a partial view of the resilient support of the monitoringdevice of FIG. 17 illustrating a textured surface thereof, according tosome embodiments of the present invention.

FIGS. 18A-18B and 19A-19B are perspective views of a monitoring devicehaving a compressible outer cover, or gel, at least partiallysurrounding a core monitoring device and configured to bias a sensingelement in a desired region of the ear, according to some embodiments ofthe present invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying figures, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Like numbers refer to like elementsthroughout. In the figures, certain layers, components or features maybe exaggerated for clarity, and broken lines illustrate optionalfeatures or operations unless specified otherwise. In addition, thesequence of operations (or steps) is not limited to the order presentedin the figures and/or claims unless specifically indicated otherwise.Features described with respect to one figure or embodiment can beassociated with another embodiment or figure although not specificallydescribed or shown as such.

It will be understood that when a feature or element is referred to asbeing “on” another feature or element, it can be directly on the otherfeature or element or intervening features and/or elements may also bepresent. In contrast, when a feature or element is referred to as being“directly on” another feature or element, there are no interveningfeatures or elements present. It will also be understood that, when afeature or element is referred to as being “connected”, “attached” or“coupled” to another feature or element, it can be directly connected,attached or coupled to the other feature or element or interveningfeatures or elements may be present. In contrast, when a feature orelement is referred to as being “directly connected”, “directlyattached” or “directly coupled” to another feature or element, there areno intervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, steps, operations, elements, components, and/or groupsthereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

It will be understood that although the terms first and second are usedherein to describe various features/elements, these features/elementsshould not be limited by these terms. These terms are only used todistinguish one feature/element from another feature/element. Thus, afirst feature/element discussed below could be termed a secondfeature/element, and similarly, a second feature/element discussed belowcould be termed a first feature/element without departing from theteachings of the present invention. Like numbers refer to like elementsthroughout.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the specification andrelevant art and should not be interpreted in an idealized or overlyformal sense unless expressly so defined herein. Well-known functions orconstructions may not be described in detail for brevity and/or clarity.

The term “about”, as used herein with respect to a value or number,means that the value or number can vary by +/− twenty percent (20%).

The term “monitoring device” includes any type of device that may beattached to or near the ear or to an appendage of a user and may havevarious configurations, without limitation.

The term “real-time” is used to describe a process of sensing,processing, or transmitting information in a time frame which is equalto or shorter than the minimum timescale at which the information isneeded. For example, the real-time monitoring of pulse rate may resultin a single average pulse-rate measurement every minute, averaged over30 seconds, because an instantaneous pulse rate is often useless to theend user. Typically, averaged physiological and environmentalinformation is more relevant than instantaneous changes. Thus, in thecontext of the present invention, signals may sometimes be processedover several seconds, or even minutes, in order to generate a“real-time” response.

The term “monitoring” refers to the act of measuring, quantifying,qualifying, estimating, sensing, calculating, interpolating,extrapolating, inferring, deducing, or any combination of these actions.More generally, “monitoring” refers to a way of getting information viaone or more sensing elements. For example, “blood health monitoring”includes monitoring blood gas levels, blood hydration, andmetabolite/electrolyte levels.

The term “physiological” refers to matter or energy of or from the bodyof a creature (e.g., humans, animals, etc.). In embodiments of thepresent invention, the term “physiological” is intended to be usedbroadly, covering both physical and psychological matter and energy ofor from the body of a creature. However, in some cases, the term“psychological” is called-out separately to emphasize aspects ofphysiology that are more closely tied to conscious or subconscious brainactivity rather than the activity of other organs, tissues, or cells.

The term “body” refers to the body of a subject (human or animal) thatmay wear a monitoring device, according to embodiments of the presentinvention.

In the following figures, various monitoring devices will be illustratedand described for attachment to the ear or an appendage of the humanbody. However, it is to be understood that embodiments of the presentinvention are not limited to those worn by humans.

The ear is an ideal location for wearable health and environmentalmonitors. The ear is a relatively immobile platform that does notobstruct a person's movement or vision. Monitoring devices located at anear have, for example, access to the inner-ear canal and tympanicmembrane (for measuring core body temperature), muscle tissue (formonitoring muscle tension), the pinna, earlobe, and elsewhere (formonitoring blood gas levels), the region behind the ear (for measuringskin temperature and galvanic skin response), and the internal carotidartery (for measuring cardiopulmonary functioning), etc. The ear is alsoat or near the point of exposure to: environmental breathable toxicantsof interest (volatile organic compounds, pollution, etc.; noisepollution experienced by the ear; and lighting conditions for the eye.Furthermore, as the ear canal is naturally designed for transmittingacoustical energy, the ear provides a good location for monitoringinternal sounds, such as heartbeat, breathing rate, and mouth motion.

Optical coupling into the blood vessels of the ear may vary betweenindividuals. As used herein, the term “coupling” refers to theinteraction or communication between excitation energy (such as light)entering a region and the region itself. For example, one form ofoptical coupling may be the interaction between excitation lightgenerated from within a light-guiding earbud and the blood vessels ofthe ear. In one embodiment, this interaction may involve excitationlight entering the ear region and scattering from a blood vessel in theear such that the temporal change in intensity of scattered light isproportional to a temporal change in blood flow within the blood vessel.Another form of optical coupling may be the interaction betweenexcitation light generated by an optical emitter within an earbud andthe light-guiding region of the earbud. Thus, an earbud with integratedlight-guiding capabilities, wherein light can be guided to multipleand/or select regions along the earbud, can assure that each individualwearing the earbud will generate an optical signal related to blood flowthrough the blood vessels. Optical coupling of light to a particular earregion of one person may not yield photoplethysmographic signals foreach person. Therefore, coupling light to multiple regions may assurethat at least one blood-vessel-rich region will be interrogated for eachperson wearing the light-guiding earbud. Coupling multiple regions ofthe ear to light may also be accomplished by diffusing light from alight source within the earbud.

Referring to FIGS. 2A-2C, a monitoring device 10 according to someembodiments of the present invention is illustrated. The illustratedmonitoring device 10 includes a biasing element 12 having opposite firstand second end portions 12 a, 12 b. An earbud 14 is attached to thebiasing element first end portion 12 a, and a sensing element 16 isattached to the biasing element second end portion 12 b. The sensingelement 16 may comprise sensor components and may preferably be smallerin mass than the mass of the earbud 14, and may be substantially less.For example, in some embodiments, the earbud mass may be at least 10%greater than the sensing element mass, may be at least 20% greater thanthe sensing element mass, may be at least 30% greater than the sensingelement mass, may be at least 40% greater than the sensing element mass,may be at least 50% greater than the sensing element mass, may be atleast 60% greater than the sensing element mass, may be at least 70%greater than the sensing element mass, may be at least 80% greater thanthe sensing element mass, may be at least 90% greater than the sensingelement mass, may be at least 100% greater than the sensing elementmass, may be 200% or more than the sensing element mass, etc. Althoughembodiments of the present invention may function sufficiently well withthe earbud 14 having a smaller mass than that of the sensor element 16,in general, the mass of the earbud is preferably larger than that of thesensor element by a sufficient degree so that the earbud serves as theprimary frame of reference (the mechanical support reference) for themonitoring device.

Substantial motion decoupling can be achieved by the sensing element 16having a mass that is smaller than the mass of the earbud 14. Forexample, if the monitoring device 10 weighs ten (10) grams and theearbud 14 has a mass of nine (9) grams and the sensor element has a massof one (1) gram, the momentum caused by the monitoring device 10accelerating may be substantially less on the sensing element 16 suchthat the sensing element 16 experiences less distance travelled. Sensornoise is reduced by stopping the monitoring device 10 momentum fromcausing the sensing element 16 to move as far. Sensor jitter frommovement is the largest controllable contributor to a noisy signal. Themore one can decouple device mass from sensor mass the cleaner thesignal gets. The more the sensing element 16 mass is reduced and thelower the spring constant, the less sensor movement is experienced fromthe monitoring device 10 mass accelerating on each footstep of thesubject, for example.

The monitoring device 10 is configured to be attached to an ear of asubject such that the earbud 14 is secured within the ear and thebiasing element 12 urges the sensing element 16 into contact with theear at a particular location, for example, as illustrated in FIG. 4. Inaddition, the biasing element 12 decouples motion of the larger massearbud 14 from the smaller mass sensing element 16. As such, the motionof sensing element 16 is more closely tied to the motion of the subjectand less tied to the motion of the earbud, for example when the subjectis exercising or undergoing other motion. For example, the motionbetween the sensing element 16 and the subject may be less than themotion between the sensing element 16 and the earbud 14.

The earbud 14 may have various shapes and configurations and is notlimited to the illustrated shape. The sensing element 16 may havevarious shapes and configurations and is not limited to the illustratedshape. In addition, a wire (not shown) may connect an audio device tothe earbud, as would be understood by those of skill in the art.Moreover, the earbud 14 may comprise a speaker, and/or the monitoringdevice 10 may generally comprise a speaker and microphone. Various typesof speakers or microphones may be used. In some cases a bone conductionmicrophone or speaker may be used. In some embodiments, a speaker mayintentionally not be present and an opening or hole may exist in theearbud to expose the ear canal to the outside world. Such an embodimentmay be useful for the case where biometric/physiological monitoring isdesired without the user's ear canal being blocked-off from ambientsounds. FIG. 4 illustrates the monitoring device 10 of FIGS. 2A-2Csecured within the ear of a person.

In some embodiments of the present invention, the sensing element 16includes at least one energy emitter 20 (FIG. 3) configured to directenergy at a target region of the ear (or for other embodiments of thepresent invention, at a target region of another portion of the body ofa subject, such as an appendage) and at least one detector 22 (FIG. 3)configured to detect an energy response signal from the target regionand/or a region adjacent the target region. For example, the at leastone energy emitter 20 is configured to direct electromagnetic radiation,mechanical energy, acoustical energy, electrical energy, and/or thermalenergy at the target region, and the at least one detector 22 isconfigured to detect electromagnetic radiation, mechanical energy,acoustical energy, electrical energy, and/or thermal energy. In someembodiments, the at least one energy emitter comprises at least oneoptical emitter and the at least one detector comprises at least oneoptical detector. Exemplary optical detectors include, but are notlimited to photodiodes, photodetectors, phototransistors, thyristors,solid state devices, optical chipsets, whether analog or digital, or thelike. Many types of compact optical detectors exist in the marketplacetoday and comprise various'well-known methods of generating analog ordigital outputs. Exemplary optical emitters include, but are not limitedto light-emitting diodes (LEDs), laser diodes (LDs), compactincandescent bulbs, micro-plasma emitters, IR blackbody sources, or thelike.

Some emitters, detectors, or emitter-detector modules may also compriseone or more processors 26 for signal conditioning, ND conversion,voltage-to-frequency conversion, level translation, and general signalprocessing of signals from the detector. Additionally, one or moreprocessors 26 may be used to control the powering (electrical biasing)of the emitters and/or detectors. A few examples are provided in U.S.Patent Application Publication No. 2012/0197093, which is incorporatedherein by reference in its entirety. In some embodiments, the processor26 may not be located within the sensing element 16 itself and may evenbe located outside of the monitoring device 10 altogether, as long asthe processor 26 is in electrical communication with the sensing element16. Moreover, processor 26 may represent multiple processors distributedwithin the monitoring device 10 and/or outside of the monitoring device10.

The energy may be pulsed energy generated by an energy emitter 20. Forexample, a pulsed driving circuit (not shown) may be used to drive atleast one energy emitter 20 at one or more pulsed frequencies tointerrogate a target region with pulsed energy. An energy responsecaused by this interaction is detected by at least one detector 22,which is configured to detect energy in the forms described above, buttypically in the form of scattered optical energy. A motion/positionsensor 24 (e.g., an inertial sensor, MEMS (micro-electro-mechanicalsystems) sensor, accelerometer, gyroscope, capacitive sensor, inductivesensor, acoustic sensor, optical sensor, piezoelectric sensor, etc.) maybe configured to measure movement, positional changes, or inertialchanges in the vicinity of the target region, such as gross body motion,skin motion, or the like. The motion/position sensor 24 may be locatedwithin the sensing element. In other embodiments, the biasing element 12may include a motion/position sensor 24 that is configured to detectmotion of the biasing element 12 and/or sensing element 16, or therelative motion between the earbud 14 and sensing element 16.

The motion/position sensor 24 may also serve as a noise reference by aneighboring or remote processor (such as processor 26) for attenuatingor removing motion noise from physiological signals picked up by thedetector 22. Noise attenuation and removal is described in detail inU.S. Pat. Nos. 8,157,730, 8,251,903, U.S. Patent Application PublicationNo. 2008/0146890, U.S. Patent Application Publication No. 2010/0217098,U.S. Patent Application Publication No. 2010/0217102, U.S. ProvisionalPatent Application No. 61/750,490, PCT Application No. US2012/071593,PCT Application No. US2012/071594, and PCT Application No.US2012/048079, which are incorporated herein by reference in theirentireties.

In some embodiments, the monitoring device 10 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the at least one detector 16. The monitoring device 10 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the at least one detector 22,one or more filters such as optical filters (snot shown) for removingthe effects of time-varying environmental interference, one or moreanalog and/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 10 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 10may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 10 and may be charged via a USB charge port, forexample.

In the illustrated embodiment of FIGS. 2A-2C, the sensing element 16includes a surface 30 that engages a portion of the ear E of a subject.In some embodiments, at least part of the surface 30 may be contoured toconform to a shape of a portion of the ear of a subject. Also, in theillustrated embodiment of FIGS. 2A-2C, one or more energy emitters 20and detectors 22 are located within the sensing element 16. A pair ofwindows 32, 34 are included in the illustrated sensing element surface30 through which energy passes from the one or more energy emitters 22,and through which energy is collected by the one or more detectors 22.Each window 32, 34 is formed from a material that allows energy to passtherethrough. For example, if an optical emitter and detector areutilized, the windows 32, 34 are formed from material that allows lightto pass therethrough. In some embodiments, the windows 32, 34 mayinclude one or more openings. In some embodiments, a single window isutilized instead of a pair of windows.

Although the windows 32, 34 illustrated in FIG. 2C may be shown as flushwith the overall sensor surface 30, it should be noted that the windows32, 34 at the sensor surface 30 may be recessed with respect to thesensor surface 30 and may not come into physical contact with the skinof the ear of a user of the monitoring device 10. A flush, protruding,or recessed window(s) (32, 34) may be acceptable. Furthermore, thewindow(s) (32, 34) in some embodiments may comprise air such that theexcitation energy entering or leaving the sensor element 16 may passthrough air.

In some embodiments of the present invention, one or both of the windows32, 34 may be in optical communication with an optical lens (not shown).The lens may be configured to focus light emitted by an optical emitteronto one or more portions of an ear and/or to focus collected light on adetector. Various types of lens geometries may be employed, such asconcave, convex, collimating, and the like. Light guides (such as lightpipes, fiber optics, or the like) may also be incorporated for thisstated purpose. Exemplary light guides and sensing element geometriesthat may be utilized in accordance with some embodiments of the presentinvention are described, for example, in U.S. Patent ApplicationPublication No. 2010/0217102, U.S. Patent Application Publication No.2013/0131519, and U.S. Patent Application Publication No. 2010/0217098,which are incorporated herein by reference in their entireties.

As will be described below, in other embodiments of the presentinvention, an optical energy emitter 20 and/or optical detector 22 maybe located within the monitoring device 10, in the earbud 14 or sensingelement 16. One or more light guides are utilized to deliver light fromthe optical emitter into an ear region of the subject via the lightguide distal end, and/or to collect light from an ear region of thesubject via the light guide distal end and deliver collected light tothe optical detector.

FIGS. 5A and 5B illustrate a monitoring device 110, according to otherembodiments of the present invention. The monitoring device 110 includesa housing 114 configured to be attached to an ear of a subject, and asensing element 116 movably secured to the housing 114 via a biasingelement 112 (e.g., a coil spring, or other substantially compressiblestructure or material, etc.). In some embodiments, the biasing element112 may include a motion sensor (not shown) that is configured to detectmotion of the biasing element 112 and/or sensing element 116.

Though non-limiting, the biasing element 112 may have a spring constantbetween about 0.1 N/m and about 200 N/m. If a resilient material isutilized as the biasing element 112, the resilient material may have adurometer range from about 10 (Type OO—ASTM D2240) to 80 (Type A—ASTMD2240), and a hardness range of about 20-50 Shore A. Exemplary springsthat may be utilized as the biasing element 112 can be molded fromacetal, polyester, polyetherimide, or another suitable polymer, or couldbe formed from metal, such as steel. Exemplary spring manufacturersinclude, but are not limited to, Lee Spring (Greensboro, N.C.) andCentury Spring Corp. (Los Angeles, Calif.). An exemplary resilientmaterial that may be used as a biasing element includes, but is notlimited to, silicone (Dow Corning Corp., Midland, Mich.). However,various other materials may be used, such as stretchy neoprene(polyurethane).

The illustrated sensing element 116 includes a printed circuit board(PCB) 123 with an optical emitter 120 and an optical detector 122attached thereto. The PCB 123 also includes an elongated guide rod 125that is inserted within the illustrated biasing element 112. It shouldbe noted that while the direction of light emission in FIG. 5A is shownradiating outwards in one embodiment, the preferred direction ofemission light is the region between the anti-tragus and concha of theear as described, for example, in U.S. Patent Application PublicationNo. 2010/0217098, U.S. Patent Application Publication No. 2010/0217102,and also in U.S. Patent Application Publication No. 2013/0131519 whichis incorporated herein by reference in its entirety. In the particularembodiment shown in FIG. 5A, optically reflective walls 126 arepositioned to direct light towards the region between the anti-tragusand concha of the ear.

The monitoring device 110 also includes a cover 118 for the sensingelement 116. The cover 118 may be transmissive to energy (e.g.,electromagnetic radiation, acoustical energy, electrical energy, and/orthermal energy, etc.) emitted by an emitter associated with the sensingelement 116 and energy detected by a detector associated with thesensing element 116. For example, if the sensing element 116 includes anoptical emitter and detector, the cover 118 may be transmissive tooptical wavelengths of the optical emitter and detector. In theillustrated embodiment, the cover 118 may also include reflectivesurfaces or walls 126 to facilitate directing energy from the emitter120 toward the ear of a user and directing energy from the ear to thedetector 122. The angle of the reflective wall(s) 126 with respect tothe axis of the elongated rod 125 is shown at approximately forty-fivedegrees (45°) in FIG. 5A, but this should not be considered limiting.The angle of the reflective walls 126 will depend primarily on thedirection of the emission/detection face of the optical emitter/detectorwith respect to the region between the anti-tragus and concha of theear. For example, if the emitter 120 and detector 122 are directed withtheir respective emission/detection faces located in the direction ofthe anti-tragus, the angle of the reflective surface(s) 126 may beninety degrees)(90° with respect to the axis of the elongated rod 125.

The illustrated cover 118 is attached to the sensing element 116 andmoves with the sensing element. The cover 118 can be attached to thesensing element 116 in various ways. For example, in some embodiments,the cover 118 may be overmolded onto the sensing element 116 such thatthe cover at least partially conforms to the shape of the sensingelement 116 components. In other embodiments, the cover 118 may beattached with a suitable transmissive adhesive. Exemplary adhesivematerials include, but are not limited to, glue, tape, resin, gel,filler material, molded material, etc. In some embodiments, the cover118 is attached to the sensing element 116 via heatstaking, one or moremechanical fasteners, or other suitable methods. In some embodiments,the sensing element 116 and cover 118 may comprise an integrated unit(via overmold and/or adhesive) that can be connected to the rod 123 orspring 112.

It should be noted that in some embodiments, an optical filter may beplaced over the emitter 120 or detector 122 in one or more ways, forexample, as described in U.S. Patent Application Publication No.2010/0217098, U.S. Patent Application Publication No. 2010/0217102, U.S.Patent Application Publication No. 2013/0131519, and U.S. PatentApplication Publication No. 2012/0197093. Additionally, the cover 118may comprise an optical filter or optical dye focused on the wavelengthof interest, which is chiefly determined by the choice of the opticalemitter 120. As an example, if 940 nm wavelength light is desired foremission by the optical emitter, in order to help overcome external(e.g., sunlight, etc.) noise pollution on the optical detector 122(e.g., as described in U.S. Patent Application Publication No.2012/0197093), then the optical filter may be tuned to the infraredrange centered around 940 nm. As a specific example of this, one may useGENTEX-E800 dye dispersed in a polycarbonate or acrylic cover 118.

In the illustrated embodiment, the housing 114 of the monitoring device110 has a much larger mass than the sensing element 116 and cover 118,and the biasing element 112 decouples motion of the housing 114 from thesensing element 116 and cover 118.

In some embodiments, the monitoring device 110 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the optical detector 122. The monitoring device 110 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the optical detector 122, oneor more filters such as optical filters (not shown) for removing theeffects of time-varying environmental interference, one or more analogand/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 110 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 110may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 110 and may be charged via a USB charge port, forexample.

FIGS. 18A-18B and 19A-19B illustrate a monitoring device 710 configuredto be attached to an ear of a subject, according to other embodiments ofthe present invention. The monitoring device 710 includes a housing 714,a core element 718, and a sensing element 716. A sound port 720 isformed in the core element and is in acoustic communication with aspeaker (not shown) within the housing 714. The sensing element 716 mayinclude all of the functionality of the sensing device 16 describedabove. For example, the sensing element 716 may include at least oneenergy emitter 20 (FIG. 3) configured to direct energy at a targetregion of the ear and at least one detector 22 (FIG. 3) configured todetect an energy response signal from the target region or a regionadjacent the target region, as described above, to sense physiologicalsignals from the body of the subject.

A cover 818 formed from compressible/resilient material, such as a gelmaterial, etc., surrounds the core element 718, as illustrated in FIGS.19A-19B. The cover 818 at least partially surrounds the sensing element716, and serves as a biasing element that decouples motion of thehousing 714 and core element 718 from the sensing element 716. Theillustrated cover 818 has a sound port 820 formed therethrough that isin acoustic communication with sound port 720

Also, as illustrated in FIGS. 19A-19B, the monitoring device 710includes an arcuate resilient member 822 that is configured to stabilizethe monitoring device 710 within the ear of a subject, as would beunderstood by one skilled in the art. Numerous types of stabilizers(also referred to as covers, tips, or housings) that may be utilized asmember 822 are well known in the art, (e.g., see U.S. Patent ApplicationPublication No. 2010/0217098, U.S. Patent Application Publication No.2010/0217102, and U.S. Patent Application Publication No. 2012/0197093)each finding various points of reference for holding an earbud withinthe ear.

The illustrated monitoring device 710 also includes an additionalflexible member 824 formed from a compressible/resilient material, suchas a gel material, etc. This flexible member 824 is attached to thecover 818 and extends below the plane of the sensing element 816, suchthat the sensing element 816 is recessed within the flexible member 824.The flexible member 824 effectively extends the cover 818 so that it cancompress in the region including, and in between, the anti-tragus andcrus helix of a subject's ear. A barrier between the emitter anddetector may also be preserved as the flexible member 824 extends toprevent optical cross-talk between the emitter and detector of thesensing element 716.

The flexible member 824 serves as a biasing element that decouplesmotion of the housing 714 and core element 718 from the sensing element716. As such, the illustrated monitoring device 710 effectively includestwo biasing elements that facilitate the decoupling of motion of thehousing 714 and core element 718 from the sensing element 716: flexiblecover 818 and flexible member 824.

In some embodiments, the monitoring device 710 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the at least one detector 22. The monitoring device 710 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the at least one detector 22,one or more filters such as optical filters (not shown) for removing theeffects of time-varying environmental interference, one or more analogand/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 710 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 710may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 710 and may be charged via a USB charge port, forexample.

In some embodiments of the present invention, as illustrated in FIGS.2A-2C, an optical emitter 20 and optical detector 22 are attached to ordisposed within the sensing element 16. However, in other embodiments ofthe present invention, an optical emitter 20 and/or optical detector 22can be located remotely from the sensing element 16. For example, asillustrated in FIG. 7, an optical emitter 20 and optical detector 22 maybe located within the earbud 14. A pair of elongated light guides 130,such as illustrated in FIG. 6, are in optical communication with theoptical emitter 20 and optical detector 22 via proximal end portions 130b and extend from the optical emitter 20 and optical detector 22 atleast partially through the biasing element 12 to the sensing element16. The sensing element 16 includes a pair of windows 32, 34 in thesurface 30 thereof. Each light guide distal end 130 a is positionedadjacent a respective window 32, 34, as illustrated. As such, the lightguide 130 in optical communication with the optical emitter 20 candeliver light from the optical emitter 20 into an ear region of thesubject, and the light guide 130 in optical communication with theoptical detector 22 can collect light from the ear region of the subjectand deliver collected light to the optical detector 22.

The distance between the sensing element windows 32 and 34 is longenough to reduce optical backscatter noise and close enough to emit anddetect light from a target region and/or a region adjacent the targetregion. Distances on the order of millimeters have been found to beideal in practice. Moreover, the material between windows 32, 34 issufficiently optically opaque to reduce cross-talk between the emitter20 and detector 22.

Each light guide 130 may be formed from various types of lighttransmissive material, typically with a refractive index greater thanabout 1.1. In some embodiments, a light guide 130 may be formed from anelastomeric light transmissive material. Exemplary light guide materialsinclude, but are not limited to, polycarbonate, acrylic, silicone, andpolyurethane. In some embodiments, a light guide 130 may be surroundedor partially surrounded by a cladding material that is configured toblock light from an external source, such as room light, sunlight, etc.,from entering the light guide 130. The distal free end surface 130 c ofeach light guide 130 may have a variety of shapes and/or configurations,more than exemplarily shown in FIG. 6. Various types and configurationsof light guides may be utilized, for example, as described in U.S.Patent Application Publication No. 2010/0217102 and U.S. PatentApplication Publication No. 2013/0131519.

As illustrated in FIG. 6, optical coupling material 132 may be appliedto one or both of the optical emitter 20 and optical detector 22. Alight guide 130 is in optical communication with the optical emitter 20and optical detector 22 via the optical coupling material 132. Theoptical coupling material 132 may comprise a material that effectivelycouples light from the optical emitter 20 to the light guide 130 or fromthe light guide 130 to the optical detector 22. Examples of suitablematerials include, but are not limited to, glue, epoxy, tape, resin,gel, oil, filler material, molded material (such as a plastic, acrylic,and/or polycarbonate) or the like.

In some embodiments of the present invention, the sensing element 16 mayhave one or more windows 32, 34 in the surface 30 thereof and the distalfree end surface 130 c of one or both of the light guides 130 may extendto the windows 32, 34. In other embodiments, one or both of the windows32, 34 may be apertures formed through the surface 30 and the distalfree end surface 130 c of one or both of the light guides 130 may extendto or through the apertures.

Referring now to FIG. 10, a monitoring device 210, according to otherembodiments of the present invention, is illustrated. The illustratedmonitoring device 210 includes a biasing element 212 having oppositefirst and second end portions 212 a, 212 b. A sensing element 216 isattached to the biasing element second end portion 212 b. The monitoringdevice 210 is configured to be attached to an ear E of a subject suchthat the biasing element first end portion 212 a engages the ear at afirst location and such that the sensing element is urged by the biasingmember into contact with the ear at a second location, as illustrated inFIG. 9. The sensing element 216 may include all of the functionality ofthe sensing device 16 described above with respect to FIGS. 2A-2C, andmay have the same overall structure as that of sensing device 16. Forexample, the sensing element 216 may include at least one energy emitter20 (FIG. 3) configured to direct energy at a target region of the earand at least one detector 22 (FIG. 3) configured to detect an energyresponse signal from the target region or a region adjacent the targetregion, as described above, to sense physiological signals from the bodyof the subject.

In some embodiments, the monitoring device 210 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the at least one detector 22. The monitoring device 210 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the at least one detector 22,one or more filters such as optical filters (not shown) for removing theeffects of time-varying environmental interference, one or more analogand/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 210 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 210may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 210 and may be charged via a USB charge port, forexample.

The illustrated embodiment of FIG. 10 does not utilize an earbud portion(e.g., 14, FIGS. 2A-2C) or a stabilization member (314, FIG. 11) forsupport within the ear. The first end portion 212 a of the monitoringdevice 210 illustrated in FIG. 10 may be supported within the earprimarily by the ear region including, and in between, the anti-helixand crus helix, as shown in FIG. 9. Alternatively, the first end portion212 a may be supported primarily by the ear region including, and inbetween, the crus helix and acoustic meatus. More generally, the firstend portion 212 a and second end portion 212 b may be supported bygeometrically opposing ear features.

The monitoring device 210 may be oriented within a subject's ear invarious ways. For example, the sensing element 216 location may be“flipped”. Referring to FIG. 9, the second end portion 212 b may besupported by the ear region including, and in between, the anti-helixand crus helix, and the first end portion 212 a may be supported by theear region including, and in between, the crus helix and anti-tragus. Inthis “flipped” orientation, the sensing element 216 may rest against theanti-helix of the ear rather than the anti-tragus. Though the anti-helixmay have substantially less blood flow than that of the anti-tragus, itmay present less motion artifacts for some user activities, and so thisconfiguration may be useful for some physiological monitoringapplications.

Referring now to FIG. 11, a monitoring device 310, according to otherembodiments of the present invention, is illustrated. The illustratedmonitoring device 310 includes a biasing element 312 having oppositefirst and second end portions 312 a, 312 b. A stabilization member 314that is configured to be at least partially inserted into the ear or earcanal is attached to the biasing element first end portion 312 a. Inthis embodiment, the stabilization member 314 may not contain a speakerand may not serve the function of an audio earbud. In some embodimentsof this configuration, because a speaker is not required, thestabilization member 314 may have a hole completely through one or moreaxes to allow sound to freely pass from the environment to the eardrumof the subject wearing the monitoring device 310. The stabilizationmember 314 facilitates attachment of the monitoring device 310 to an earof a subject.

The monitoring devices 210 and 310 may be particularly useful forsubjects who want to monitor their vital signs but do not want to listento music or do not want to have their ear canal blocked-off from sound.Additionally, if constructed with waterproof housing, the monitoringdevices 210 and 310 may be especially suited for swimmers who may notwant to hear sound from speakers during physiological monitoring.

A sensing element 316 is attached to the biasing element second endportion 312 b. The monitoring device 310 is configured to be attached toan ear E of a subject such that the sensing element 316 is urged by thebiasing member 312 into contact with the ear, as illustrated in FIG. 8.The sensing element 316 may include all of the functionality of thesensing device 16 described above. For example, the sensing element 316may include at least one energy emitter 20 (FIG. 3) configured to directenergy at a target region of the ear and at least one detector 22 (FIG.3) configured to detect an energy response signal from the target regionor a region adjacent the target region, as described above, to sensephysiological signals from the body of the subject. With the illustratedconfiguration of the monitoring device 310, the sensing element 316 maybe preferably biased to direct and/or detect energy from the region ofthe ear between the anti-tragus and concha of the ear, as this regionhas been found to provide a sufficiently high blood flow signalintensity while also being resilient to motion artifacts.

In some embodiments, the monitoring device 310 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the at least one detector 22. The monitoring device 310 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the at least one detector 22,one or more filters such as optical filters (not shown) for removing theeffects of time-varying environmental interference, one or more analogand/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 310 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 310may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 310 and may be charged via a USB charge port, forexample.

The small size of the monitoring devices 210 and 310 may preclude spacefor signal processing electronics (26) and battery power. For thisreason, these monitoring devices may also be attached/wired toadditional structures that house necessary electronics and/or batterypower. Various configurations can be used for these additionalstructures and are well known to those skilled in the art. For example,the monitoring devices 210, 310 may be wired to a smartphone, wireless“medallion”, and/or MP3-player for powering, signal processing, oraudiovisual communication. Moreover, at least some of the electronicsillustrated in FIG. 3 may be located in such additional structures,rather than in the monitoring devices 210, 310, themselves.

Referring now to FIGS. 12 and 13, a monitoring device 410, according toother embodiments of the present invention, is illustrated. Theillustrated monitoring device 410 includes a sensor band 420 configuredto be secured to an appendage A (e.g., an arm, wrist, hand, finger, toe,leg, foot, neck, etc.) of a subject, and a sensing element 416 movablysecured to the sensor band 420 via a biasing element 412. The biasingelement 412 is configured to urge the sensing element 416 into contactwith a portion of the appendage A. The biasing element 412 decouplesmotion of the sensor band 420 from the sensing element 416.

The sensor band 420 has a first mass, and the sensing element 416 has asecond mass that is less than the first mass. For example, in someembodiments, the sensor band mass may be at least 10% greater than thesensing element mass, may be at least 20% greater than the sensingelement mass, may be at least 30% greater than the sensing element mass,may be at least 40% greater than the sensing element mass, may be atleast 50% greater than the sensing element mass, may be at least 60%greater than the sensing element mass, may be at least 70% greater thanthe sensing element mass, may be at least 80% greater than the sensingelement mass, may be at least 90% greater than the sensing element mass,may be at least 100% greater than the sensing element mass, may be 200%or more than the sensing element mass, etc. In general, the mass of thesensor band is preferably larger than that of the sensing element by asufficient degree so that the sensor band serves as the primary frame ofreference (the mechanical support reference) for the monitoring device.

The sensing element 416 may include all of the functionality of thesensing device 16 described above. For example, in summary, the sensingelement 416 may include at least one energy emitter 20 (FIG. 3)configured to direct energy at a target region of the appendage A and atleast one detector 22 (FIG. 3) configured to detect an energy responsesignal from the target region or a region adjacent the target region, asdescribed above, to sense physiological signals from the body of thesubject. In some embodiments, the biasing element 412 includes a motionsensor (e.g., 24, FIG. 3) configured to detect motion of the biasingelement and/or sensing element 416.

In some embodiments, the monitoring device 410 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the at least one detector 22. The monitoring device 410 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the at least one detector 22,one or more filters such as optical filters (not shown) for removing theeffects of time-varying environmental interference, one or more analogand/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 410 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 410may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 410 and may be charged via a USB charge port, forexample.

In some embodiments, light guides and associated optics, as shown inFIGS. 6 and 7, may be integrated into the sensing element 416 (and 516,FIG. 14). As with the earpiece monitoring device 10 described above, thesensing element 416 may additionally include at least one energy emitterand/or at least one energy detector configured to primarily sense themotion the sensor element 416 itself, such that, utilizing a processor(e.g., 26, FIG. 3), this motion signal can provide a suitable motionnoise reference for attenuating motion noise from the physiologicalsignals collected by the sensing element 416.

In some embodiments, the sensor element 416 may include a top portion441 and an opposite bottom portion 443. An energy emitter and/ordetector may be located on the bottom portion 443 to sense physiologicalinformation from the appendage of a subject wearing the monitoringdevice 410, and an energy emitter and/or detector may be located on thetop portion 441 to sense motion of the sensor element 416 with respectto the sensor band 420, counterweight 422, and/or inner surface 442 ofthe sensor band 420. Energy scattered between the top portion 441 of thesensor element 416 and inner surface 442 of the sensor band 420 maycoincide with motion between these two surfaces (i.e., sensing elementtop portion 441 and sensor band inner surface 442), and this informationmay be used as a noise reference for motion noise attenuation asaforementioned.

In some embodiments, an emitter and/or detector may alternatively bedisposed on the inner surface 442 of the sensor band 420, rather than onthe top portion 441 of the sensor element 416, or there may be at leastone emitter and detector disposed between the inner surface 442 andsensing element top portion 441. In either embodiment, energy is emittedby at least one energy emitter disposed on at least one face (i.e.,sensor band inner surface 442, sensing element top portion 441), ismodulated in intensity by motion (displacement) between the two portions(i.e., sensor band inner surface 442, sensing element top portion 441),and is detected by an energy detector disposed on at least one of thetwo portions (i.e., sensor band inner surface 442, sensing element topportion 441). It should be noted that embodiments of the presentinvention may apply equally well to the earpiece monitoring device 10 ofFIG. 2, with respect to the corresponding face of the main body of themonitoring device 10 and the corresponding face of the sensing element16.

In the illustrated embodiment, the monitoring device 410 may include asecond band 430 that is configured to be secured to the appendage A ofthe subject in adjacent, spaced-apart relationship with the sensor band420. At least one connecting member or bridge 432 connects the sensorband and second band. In general, the purpose of the bridge 432 is to atleast partially decouple motion between the sensor band 420 and secondband 430. A plurality of connecting members 432 may be utilized, withoutlimitation. The at least one connecting member 432 may be placed at adistance from the sensing element 416 to increase decoupling of motionof the sensor band 420 from the sensing element 416.

Adding a second band 430 may not be required for overall physiologicalsensing; however, having a second band 430 may help in furtherdecoupling the sensing element 416 from the motion of other essentialelectronics surrounding the appendage. For example, the second band 430may contain a power source (e.g., a battery, etc.) and various heavierelectronic components. In such case, the second band 430 may have a massthat is greater than the mass of the sensor band 420 which, in turn, mayhave a mass greater than that of the sensing element 416. In someembodiments, a counterweight 422 may be embedded within, or otherwiseattached to, the sensor band 420 to help keep the sensing element 416pressed into the appendage A of the subject.

In some embodiments, the counterweight 422 may be located in an area ofthe sensor band 420 that is opposite that of the sensing element 416. Inother embodiments, the counterweight 422 may be a distributed weightthat is distributed according to a mathematical function factoring thedistance from the sensing element 416. As a particular example, thedensity of the counterweight 422 may be proportional to the radialdistance away from the sensing element 416 such that the peak density isin an area of the sensor band 420 that is opposite that of the sensingelement 416. The counterweight 422 can be virtually any material thatcan be structurally supported by the sensor band 420. In someembodiments, the counterweight 422 may be a greater total mass ofplastic used in the housing of the sensor band 420, or a higher densityplastic.

In embodiments where one or more light-guides are integrated into thesensing element 416, a light guide may transmit light to the second band430 through the connecting member 432, such that the emitter and/ordetector electronics may also be located on the second band 430. Thismay further reduce the overall mass of the sensing element 416 and/orsensor band 420.

In some embodiments, one or more motion sensors (e.g., 24, FIG. 3) maybe integrated into multiple regions of the overall band 410. Forexample, one or more motion sensors may be located in the sensor band420, second band 430, the biasing element 412, and/or the sensor element416. Each of these regions may have different motion characteristicsdepending on the type of user motion, and the resulting motion artifactsmay corrupt the physiological signal as detected by the detector (e.g.,22, FIG. 3) associated with the sensing element 416. A processor (e.g.,26, FIG. 3) may combine signals (via mixing, averaging, subtracting,applying a transform, and/or the like) from each motion sensor to moreeffectively characterize the motion noise and thereby facilitates moreeffective attenuation of motion artifacts from physiological signalsdetected by a detector of the sensing element 416. Moreover, because themotion signals from each motion sensor may be different during usermotion, the processor may additionally be configured to identify thetype of user motion by processing the motion signals from multiplemotion sensors. As a specific example, there are many examples known tothose skilled in the art for utilizing the characteristic multi-axisaccelerometer output signals—i.e., the intensities, frequencies, and/ortransient responses of multiple accelerometers placed in differentlocations—measured during a characteristic motion for characterizingdifferent types of movement.

Embodiments of the present invention are not limited to the illustratedarrangement of the sensor band 420 and second band 430. In otherembodiments of the present invention, the arrangement of the sensor band420 and second band 430 relative to each other may be switched from thatillustrated in FIG. 12. In some embodiments, the sensor band 420 may beattached to a pair of second bands 430 such that the sensor band ispositioned between each second band (e.g., a central sensor band 420with a second band 430 on each side of the sensor band 420). Variousconfigurations of bands may be utilized in accordance with embodimentsof the present invention, as long as the weight of the sensor band 420and second band 430 are substantially decoupled, such that the bands arenot rigidly coupled together.

Referring to FIGS. 14 and 15, a monitoring device 510, according toother embodiments of the present invention, is illustrated. Theillustrated monitoring device 510 includes a band 520 that is configuredto be secured to an appendage (e.g., an arm, wrist, finger, toe, leg,neck, etc.) of a subject. The band 520 includes an inner surface 520 aand an outer surface 520 b. A plurality of biasing elements 512 extendradially outward from the inner surface 520 a in spaced-apartrelationship and are configured to contact the appendage. A sensingelement 516 is secured within one of the biasing elements 512. Asillustrated in FIG. 15, the sensing element 516 is recessed within oneof the biasing elements such that an energy emitter 20 and a detector 22are not in contact with the appendage but remain stabilized with respectto the appendage by the biasing elements 512. In another embodiment, thesensing element 516 may extend outwardly from the biasing element 512such that an energy emitter 20 and a detector 22 are in contact with theappendage and remain stabilized with respect to the appendage.

The biasing elements 512 may be formed from silicone, polymericmaterial, rubber, soft plastic, other elastomeric materials, or othercompressible materials that can act as cushions. In some cases, thebiasing elements 512 may be fluid filled solid elements or may beheterogeneous elements composed of one or more compressible materials,layers, and/or over-molded parts. Various shapes, configurations, andmaterials may be utilized to implement the biasing elements 512, withoutlimitation. The biasing elements 512 help keep the sensing element 516in place in proximity to (or against) an appendage. The biasing elements512 may have a durometer range from about 10 (Type OO—ASTM D2240) to 80(Type A—ASTM D2240), and a hardness range of about 20-50 Shore A.Exemplary resilient material that may be used as a biasing element 512includes, but is not limited to, silicone (Dow Corning Corp., Midland,Mich.). However, various other materials may be used.

The sensing element 516 may include all of the functionality of thesensing device 16 described above. For example, the sensing element 516may include at least one energy emitter 20 (FIG. 3) configured to directenergy at a target region of the appendage and at least one detector 22(FIG. 3) configured to detect an energy response signal from the targetregion and/or a region adjacent the target region, as described above.In some embodiments, one or more of the biasing elements 512 includes amotion sensor (not shown) configured to detect motion of the biasingelement 512 and/or sensing element 516.

In some embodiments, the monitoring device 510 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the at least one detector 22. The monitoring device 510 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the at least one detector 22,one or more filters such as optical filters (not shown) for removing theeffects of time-varying environmental interference, one or more analogand/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 510 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 510may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 510 and may be charged via a USB charge port, forexample.

Alternating shapes of the biasing elements 512 may be useful forproviding additional mechanical support as different shapes touching theskin may product stabilizing forces in different vectors (directionsand/or magnitudes) across the skin which collectively may provide anoverall better support of the band 520 against an appendage.

Referring to FIGS. 16 and 16A, a monitoring device 510, according toother embodiments of the present invention, is illustrated. Theillustrated monitoring device 510 includes a band 520 that is configuredto be secured to an appendage (e.g., an arm, wrist, finger, toe, leg,neck, hand, foot, etc.) of a subject. The band 520 includes an innersurface 520 a and an outer surface 520 b. A plurality of biasingelements 512 extend radially outward from the inner surface 520 a inspaced-apart relationship and are configured to contact the appendage. Asensing element 516 is secured to the band inner surface 520 a betweenadjacent biasing elements 512. In some embodiments, the sensing element516 extends outwardly from the band inner surface 520 a such that anenergy emitter 20 and a detector 22 are not in contact with theappendage but remain stabilized with respect to the appendage by thebiasing elements. In other embodiments, the sensing element 516 extendsoutwardly from the band inner surface 520 a such that an energy emitter20 and a detector 22 are in contact with the appendage and remainstabilized with respect to the appendage.

Alternating shapes of the biasing elements 512 may be useful forproviding additional mechanical support as different shapes touching theskin may product stabilizing forces in different vectors (directionsand/or magnitudes) across the skin which collectively may provide anoverall better support of the band 520 against an appendage.

Referring to FIGS. 17, 17A and 17B, a monitoring device 610, accordingto other embodiments of the present invention, is illustrated. Theillustrated monitoring device 610 includes a band 620 that is configuredto be secured to an appendage (e.g., an arm, wrist, finger, toe, leg,neck, hand, foot, etc.) of a subject. The band 620 includes an innersurface 620 a and an outer surface 620 b. A single, elongated biasingelement 612 is located on the inside of the band 620 near the innersurface 620 a. The biasing element 612 is configured to compress andconform to the appendage of a subject when the band is worn on theappendage. The biasing element 612 has opposite ends 612 a, 612 b andthe biasing element 612 extends circumferentially around the band innersurface 620 a such that the biasing element ends are in adjacent,spaced-apart relationship.

A sensing element 616 is secured to the band inner surface 620 a betweenthe spaced-apart end portions 612 a, 612 b of the biasing element 612.In some embodiments, the sensing element 616 extends outwardly from theband inner surface 620 a such that an energy emitter 20 and a detector22 are not in contact with the appendage but remain stabilized withrespect to the appendage by the biasing element 612. In otherembodiments, the sensing element 616 extends outwardly from the bandinner surface 620 a such that an energy emitter 20 and a detector 22 arein contact with the appendage and remain stabilized with respect to theappendage. The sensing element 616 may include all of the functionalityof the sensing device 16 described above. For example, the sensingelement 616 may include at least one energy emitter 20 (FIG. 3)configured to direct energy at a target region of the ear and at leastone detector 22 (FIG. 3) configured to detect an energy response signalfrom the target region or a region adjacent the target region, asdescribed above.

In some embodiments, the monitoring device 610 includes a signalprocessor 26 (FIG. 3) that is configured to receive and process signalsproduced by the at least one detector 22. The monitoring device 610 mayinclude other components such as one or more analog-to-digitalconvertors (not shown) for the output of the at least one detector 22,one or more filters such as optical filters (not shown) for removing theeffects of time-varying environmental interference, one or more analogand/or digital filters for removing motion artifacts in an energyresponse signal, passive electronic components, etc., as would beunderstood by one skilled in the art. The monitoring device 610 mayinclude various other devices, such as other types of physiologicalsensors and environmental sensors (not shown). The monitoring device 610may also include at least one wireless module (not shown) forcommunicating with a remote device, and/or at least one memory storagedevice (not shown). An exemplary wireless module may include a wirelesschip, antenna, or RFID tag. In some embodiments, the wireless module mayinclude a low-range wireless chip or chipset, such as a Bluetooth®,ANT+, and/or ZigBee chip. A battery (not shown), such as a lithiumpolymer battery or other portable battery, may be included within themonitoring device 610 and may be charged via a USB charge port, forexample.

One or more portions (including all) of the biasing element surface 612a that engages the skin have a textured configuration. In theillustrated embodiment of FIG. 17B, the portion of the surface 612 awith a textured configuration includes a plurality of raised portions orprotrusions 614. These protrusions 614 facilitate breathability of theband 620 when touching the skin. The textured surface portions may havevirtually any shape to support spring compression and breathability, butspherical protrusions or flat protrusions may be best for manufacturingsimplicity and comfort. In some embodiments the protrusions 614 may havea height, spacing, and diameter in the range of between about 0.1 mm andabout 5.0 mm. For example, a protrusion 614 may have a height of betweenabout 0.1 mm and about 5.0 mm, a diameter of between about 0.1 mm andabout 5.0 mm, and adjacent protrusions 614 may be spaced apart betweenabout 0.1 mm and about 5.0 mm. However, various other ranges arepossible.

In some embodiments, alternating shapes of textured portions may beuseful for providing additional mechanical support as different shapestouching the skin may product stabilizing forces in different vectors(directions and/or magnitudes) across the skin which collectively mayprovide an overall better support of the band 620 against the appendage

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the teachings andadvantages of this invention. As an example, although many drawings inthis invention have shown sensing elements located within the innerregion of the ear, the invention could be applied to designs where thesensing element is configured to be placed on the outside of the ear,such as a location behind the earlobe or in front of the tragus.Accordingly, all such modifications are intended to be included withinthe scope of this invention as defined in the claims. The invention isdefined by the following claims, with equivalents of the claims to beincluded therein.

That which is claimed is:
 1. A monitoring device, comprising: a sensorband configured to be secured around an appendage of a subject, whereinthe sensor band has a first mass; a sensing element secured to thesensor band, wherein the sensing element has a second mass that is lessthan the first mass; a second band configured to be secured to theappendage of the subject in adjacent, spaced-apart relationship with thesensor band; and at least one member connecting the sensor band and thesecond band.
 2. The monitoring device of claim 1, wherein the sensingelement is movably secured to the sensor band via a biasing element,wherein the biasing element is configured to urge the sensing elementinto contact with a portion of the appendage, wherein the biasingelement at least partially decouples motion of the sensor band from thesensing element, and wherein the at least one member at least partiallydecouples motion between the sensor band and the second band.
 3. Themonitoring device of claim 1, wherein the second band has a third massthat is greater than the first mass.
 4. The monitoring device of claim1, wherein the sensor band comprises at least one counterweightconfigured to help urge the sensing element into contact with theappendage of the subject.
 5. The monitoring device of claim 1, whereinthe sensing element comprises at least one energy emitter configured todirect energy at a target region of the appendage and at least onedetector configured to detect an energy response signal containingphysiological information from the target region or a region adjacent tothe target region.
 6. The monitoring device of claim 5, furthercomprising at least one filter configured to at least partially removemotion artifacts from the energy response signal.
 7. The monitoringdevice of claim 5, further comprising at least one wireless moduleconfigured to communicate with a remote device.
 8. The monitoring deviceof claim 5, further comprising a signal processor configured to receiveand process signals produced by the at least one detector.
 9. Themonitoring device of claim 5, wherein the at least one energy emitter isconfigured to direct electromagnetic radiation, mechanical energy,acoustical energy, electrical energy, and/or thermal energy at thetarget region, and wherein the at least one detector is configured todetect electromagnetic radiation, mechanical energy, acoustical energy,electrical energy, and/or thermal energy.
 10. The monitoring device ofclaim 5, wherein the at least one energy emitter comprises at least oneoptical emitter and wherein the at least one detector comprises at leastone optical detector.
 11. The monitoring device of claim 10, furthercomprising at least one filter configured to remove time-varyingenvironmental interference from signals produced by the at least oneoptical detector.
 12. The monitoring device of claim 10, wherein thesensing element comprises at least one light guide in opticalcommunication with the at least one optical emitter and/or the at leastone optical detector, wherein the at least one light guide deliverslight from the at least one optical emitter to the target region and/ordelivers an optical energy response signal containing physiologicalinformation from the target region or a region adjacent to the targetregion to the at least one optical detector.
 13. The monitoring deviceof claim 5, wherein the sensing element comprises a surface having atleast one window through which energy passes from the at least oneenergy emitter, and through which energy is collected by the at leastone detector.
 14. The monitoring device of claim 1, wherein the firstmass is at least about 1.25 times greater than the second mass.
 15. Themonitoring device of claim 2, wherein the biasing element comprises amotion sensor configured to detect motion of the biasing element and/orsensing element.
 16. The monitoring device of claim 1, wherein thesensing element comprises first and second portions, and furthercomprising at least one energy emitter and at least one detector locatedat the first portion to sense physiological information from theappendage of the subject, and further comprising an additional energyemitter and detector located at the second portion to sense motion ofthe sensing element with respect to the sensor band.
 17. The monitoringdevice of claim 1, wherein the sensing element comprises first andsecond portions, and further comprising at least one energy emitter andat least one detector located at the first portion to sensephysiological information from the appendage of the subject, and whereinthe sensor band comprises an additional energy emitter and detectorconfigured to sense motion of the sensing element second portion withrespect to the sensor band.
 18. The monitoring device of claim 1,wherein the second band comprises at least one optical emitter and atleast one optical detector, and further comprising at least one lightguide integrated into the sensing element that is in opticalcommunication with the at least one optical emitter and the at least oneoptical detector via the at least one member connecting the sensor bandand the second band, wherein the at least one light guide delivers lightto the target region from the at least one optical emitter and deliversan optical energy response signal containing physiological informationfrom the target region or a region adjacent to the target region to theat least one optical emitter.
 19. The monitoring device of claim 8,wherein the sensor band comprises a plurality of motion sensors, andwherein the signal processor is configured to combine signals from themotion sensors and attenuate motion artifacts from the signals producedby the at least one detector.
 20. A monitoring device, comprising: asensor band configured to be secured around an appendage of a subject,wherein the sensor band has a first mass; a sensing element secured tothe sensor band, wherein the sensing element has a second mass that isless than the first mass, wherein the sensing element comprises at leastone optical emitter configured to direct optical energy at a targetregion of the appendage and at least one optical detector configured todetect an optical energy response signal containing physiologicalinformation from the target region or a region adjacent to the targetregion; a second band configured to be secured to the appendage of thesubject in adjacent, spaced-apart relationship with the sensor band; andat least one member connecting the sensor band and the second band. 21.The monitoring device of claim 20, wherein the sensing element ismovably secured to the sensor band via a biasing element, wherein thebiasing element is configured to urge the sensing element into contactwith a portion of the appendage, wherein the biasing element at leastpartially decouples motion of the sensor band from the sensing element,and wherein the at least one member at least partially decouples motionbetween the sensor band and the second band.
 22. The monitoring deviceof claim 20, wherein the second band has a third mass that is greaterthan the first mass.
 23. The monitoring device of claim 20, wherein thesensor band comprises at least one counterweight configured to help urgethe sensing element into contact with the appendage of the subject. 24.The monitoring device of claim 20, further comprising at least onefilter configured to at least partially remove motion artifacts from theoptical energy response signal.
 25. The monitoring device of claim 20,further comprising at least one wireless module configured tocommunicate with a remote device.
 26. The monitoring device of claim 20,further comprising a signal processor configured to receive and processsignals produced by the at least one optical detector.
 27. Themonitoring device of claim 20, further comprising at least one filterconfigured to remove time-varying environmental interference fromsignals produced by the at least one optical detector.
 28. Themonitoring device of claim 20, wherein the sensing element comprises atleast one light guide in optical communication with the at least oneoptical emitter and/or the at least one optical detector, wherein the atleast one light guide delivers light from the at least one opticalemitter to the target region and/or delivers an optical energy responsesignal containing physiological information from the target region or aregion adjacent to the target region to the at least one opticaldetector.
 29. The monitoring device of claim 20, wherein the sensingelement comprises a surface having at least one window through whichoptical energy passes from the at least one optical emitter, and throughwhich optical energy is collected by the at least one optical detector.30. The monitoring device of claim 20, wherein the first mass is atleast about 1.25 times greater than the second mass.
 31. The monitoringdevice of claim 21, wherein the biasing element comprises a motionsensor configured to detect motion of the biasing element and/or sensingelement.
 32. The monitoring device of claim 20, wherein the sensingelement comprises first and second portions, and wherein the at leastone optical emitter and the at least one optical detector are located atthe first portion to direct optical energy at the target region of theappendage and to detect the optical energy response signal containingphysiological information from the target region or a region adjacent tothe target region, and further comprising an energy emitter and detectorlocated at the second portion to sense motion of the sensing elementwith respect to the sensor band.
 33. The monitoring device of claim 20,wherein the sensing element comprises first and second portions, andwherein the at least one optical emitter and the at least one opticaldetector are located at the first portion to direct optical energy atthe target region of the appendage and to detect the optical energyresponse signal containing physiological information from the targetregion or a region adjacent to the target region, and wherein the sensorband comprises an energy emitter and detector configured to sense motionof the sensing element second portion with respect to the sensor band.34. The monitoring device of claim 26, wherein the sensor band comprisesa plurality of motion sensors, and wherein the signal processor isconfigured to combine signals from the motion sensors and attenuatemotion artifacts from the signals produced by the at least one opticaldetector.